It is known that 2-[{4-(3-methoxypropoxy)-3-methylpyridin-2-yl}methylsulfinyl]-1H-benzimidazole alkali metal salts have a gastric acid secretion inhibiting action and are thus useful as anti-ulcer drugs (see Patent Document 1: U.S. Pat. No. 5,045,552). Moreover, such a salt can be produced using any of various processes, in particular a production process using a freeze drying method is known (see Patent Document 2: Japanese Patent Application Laid-Open No. H7-278141, or Patent Document 3: International Publication No. WO03/101452).
However, with the freeze drying method, large-scale equipment is required in actual production of 2-[{4-(3-methoxypropoxy)-3-methylpyridin-2-yl}methylsulfinyl]-1H-benzimidazole alkali metal salts, and moreover the method cannot necessarily be said to be excellent in terms of workability, operability and energy conservation.